Control system for motor-generator locomotives



Aug. 29, 1933- D. R. STAPLES ET AL CONTROL SYSTEM FOR MOTOR GENERATORLOCOMOTIVES Filed Jan. 18, 1929 2 Sheets-Sheet l INVENTORS Dana R.Sraples &

- Elden I-S'l'aples ATTORNEY Aug. 29, 1933. D. R. STAPLES El AL1,924,332

CONTROL SYSTEM FOR MOTOR GENERATOR LOCOMOTIVES Filed Jan. 18, 1929 2Sheets-Sheet 2 INVENTORS Dana R .Staples z gden LSfaples ATi'ORNEYPatented Aug. 29, 191i?) v UNITED STATES, PATENT OFFICE CONTROL SYSTEMFOR MOTOR-GENERA- TOR LOCOMOTIVES Dana R. Staples, Wilkinsburg, andElden I.

Staples,'Pittsburgh, Pa., assignors to Westinghouse Electric andManufacturing Company, a

Q corporation of Pennsylvania Application January 18, 1929. Serial No.333,380

I 6 Claims. (Cl.-172-239) This invention relates to electric locomotivesswitches which are closed for the various posiand particularly tolocomotives of the motor-gem tions of the master controller.

erating type. Referring now to the drawings and particularly An ob ectof the invention is to provide a moto Fig. 1, a motor-generator typelocomotive is tor-generator locomotive that shall be simple inillustrated which comprises, in general, a directconstruction andeflicient in its operation. current traction motor 1, a direct-currentgen- Another object of the invention is to provide erator 2, adirect-current exciter generator'3, an for the reduction of rheostaticlosses incident to alternating-current single-phase synchronous theacceleration of electric motor vehicles. 1 motor 4 and an autotransformer T disposed for A further object of the invention is toprovide connection to an alternating current trolley con- 65 for theinitiating of regenerative braking by actuductor 5. The generators 2 and3 and the mo- Y. 1

atirig the controller handle towards the-01f potor 4 are mechanicallycoupled to a shaft 6. sition. The motor 1 and generator 2 are preferablyof A further object of the invention is to provide the compound woundtype. As shown the motor 157 an electric locomotive, of themotor-generator 1 comprises an armature 8, a series field winding 7type, with means for connecting and disconnect- 9 and a separatelyexcitedfield Winding 10. ing the propelling or traction motors from'theThe generator 2 comprises an armature 11, a generator when the voltageof the generator is series field winding 12 and a separately excited.approximately equal to the counter-electromofield winding 13. 1 tiveforce of the traction motors. The operation of the motor 1 and thegenerator 75 A still further object of the invention is to 2 maybecontrolled by a controller 14 .of'the provide for the interruptionandre-application drum type. of the power supply to a traction motorwhile the Thesynchronous motor 4 comprises a woundmotor vehicle iscoasting without causing shock to rotor winding 15 and a single-phasestator winda train propelled by the vehicle, or the opening ing 16.Since the motor 4 is of the single-phase 0 'of the circuit breakers orother protective devices alternating current type it is notself-starting,

which may result from an abnormal regenerated therefore, in order tofacilitate the .starting of current. I the synchronous motor 4 thegenerator 3 may A still further'object oi the inventionis to probeutilized as a motor for accelerating the rotor vide for the interruptionofa regenerative brak 15 of the motor 4 toa speed at which the motor ingoperation, in the event that emergency brakwill operate as an inductionmotor.. In order to J ing, byimeans of air brakes or other type of causethe motor 4 to operate as. an induction brakes, becomes necessary.motor, a resistor'1'7 and a movable contact mem- A still further objectof the invention is to ber 18 are provided for shunting therotor'windrovide for disconnecting the traction motor from ing 15. Y 9 0the generator the moment the current flow 'be- In order to connect theexciter generator 3 to tween them drops to a predetermined value.operate asa motor, a starting push button switch And a still furtherobject of the invention is to leis provided. provide for quicklyinterrupting the power sup- In this embodiment of the invention when theply to the traction motors of a motor vehicle starting switch 19 isactuated, a circuit is estabeither in case of emergency braking orduring lished for the actuating coil of a switch 20, which light load,as for example, whenit may be desired is disposed to connect thegenerator 3 across-a V to alternately apply or interrupt the powersupbattery 21. ply to the traction motors when the motor ve- The actuatiCircuit for the Switch 20 y be 45 hicle is coasting or drifting. tracedfrom the battery 21 through conductors For a fuller understanding of theinvention, 22 and 23, junction point23", a stop push-button" referenceshould be had to the following descrip switch 24 which normally standsclosed, contion taken in conjunction with the accompany ductor 25, theactuating coil' of switch 20:, the ing drawings in which, i startingswitch 19 and conductors 26 and .27 back 50, Figure 1 is a schematicillustration of the cirto the battery 21. v H :l cuits and apparatus ofa locomotive arranged in The switch 20 is closed and a circuit foroperat accordance with the invention; ing-the generator 3 as a motorestablished which Fig. 2 is a simplified diagram of the systemcircuitmay be traced from the junction point23' shown in Fig. l; andthrough conductor 28, contact members .29

55 3 is a sequence chart illustrating the i d y theupp r conta tpl teofswitch 20, 1

.series field winding 30 of the exciter generator 3, armature 31, shuntfield winding 32 and conductors Y26 and 27 back to the battery 21.Further upon the closure or" the switch 29, a shunt is connected aroundthe starting switch 19 and a holding circuit established which extendsfrom the energized conductor 25 through the actuating coil of the switch26, conductor 25, the con-.

tact members 33 bridged by the lower contact plate of switch 20 toconductor 26. Therefore, the starting switch 19 may be released to itsopen circuit position.

When the exciter 3 is operated as a motor, it will accelerate the motor4 toa speed at which it will begin operating as an induction motor ifthe stator winding 15 is energized. When the rotor winding 15 of themotor 4 is being rotated,

a switch S may be closed so as to connect the,

auto-transformer T to the trolley conductor 5. The auto-transformer Tbeing energized, the stator winding 16 of the motor 4 will also beenergized and the motor 4 will begin to operate as rotor winding 15andconductors 36 and 27 back to the battery. Since the rotor winding 15is energized with direct current, the motor 4 will .pull into step andoperate at synchronous speed.

Assuming that it is desired tostart and accelerate the vehicle (notshown) propelled by the motor 1, the controller 14 may be actuated toposition a or its first running position. In this position, energizingcircuits are established for actuating coils of switches 37 and 38.-

When the switch 3'7 is closed, the fieldwindings 10 and 13 of the motor1 and the generator 2, respectively, are connected across the battery21. Upon the closing of the switch 38, the armature 8 of the motor isconnected across the armature 11 of the. generator.

The circuit established for the actuating coil of the switch 3'7 may betraced from the battery 21, conductor 22, junction joint 39, conductor40, contact fingers 41 and 42, bridged by contact segment 43 of thecontroller 14, conductor 44, the actuating coil of the switch 37 andconductor 27 back to the battery 21.

The circuit for the field winding 10 may be traced from junction point39 through conductor 7 45, the contact members of'the switch 37,conductor 46, resistor 47, conductor 48, the field Winding 10 andconductors 67 and 27 back to the battery 21.

The circuit established for the field winding 13 of the generator 2 maybe traced from the junction point 39, conductor 45, contact members of 1the switch 37, conductor 46, resistor 49, conductor 50, field winding13, and conductors 26v and2'7 to the battery 21.

- The circuit established for the actuating coil of troller 14-conductor52, the actuating coil of the switch 38,1'1ormally closed contactmembers 53 of a differential relay 54, conductors 55 and 27 back to thebattery 21. i I

, The motor circuit established when the switch 38 is closed may betraced from the armature 11 of the generator 2 through conductor 56,contact members of the switch 38, conductor 57, the armature 8, seriesfield winding 9 of the motor 1, an

actuating coil 58 of a current responsive relay 59, and series fieldwinding 12 of the generator 2 back to the armature 11. v

The differential relay 54 comprises an armature 60 and seriesconnectedactuating coils 61 and 62. It will be observedthat the coils 61 and'62are connected across the Jarmatures of the generator 2 and the motor 1,respectively, through a common conductor 63, and are disposed to openthe contact members 53 of the relay 54 when the voltrotating, and thegenerator 2 is developing a volt-.

age, the'contact members of the relay maybe biased towards a closed.position by a spring 64. It will be observed that when the switch 38 hasbeen closed, the Voltage impressed onthe respective coils 61 and 62 willbe equal and since the coils are in opposition there will be noresultant pullon the armature 60 tending to open the contact members ofthe relay. .Since the contact members of the relay will not open underthese conditions, the switch 38vvill remain closed unless the actuatingcoil thereof is deenergized by operation or the controller 14.

When the motor 1 has been connected across the generator2 'bythe closingof the switch 38, 7 current will flow from the generator to the motorwhich current will energize the actuating coil58 of the relay 59 wherebycontact members. 66 of the relay will be closed to provide acircuitaround .the contact members 53 of the relay 54.

Therefore, .the actuating coil or the switch 38 will be maintainedenergized even though the contact .members 53 of the relay 54 should beopened.

The circuit established around or parallel to the contact members 53 maybe traced from the conductor 27 through conductors 6'7 and 68, thecontact members 66 of the relay59, conductor 69, the coil ofthe switch38, conductor 52 and contact members 51 and 41 bridged by the contactsegment 43 of the controller 14 to the junction point 39. It is to beobserved thatwhen the current flowing through thecoil 58 of the relay 59falls below a. predetermined value, the contact members 66 thereof willbe opened.

When the controller 1.4 is actuated toposition I) contact fingers '73,'74 and 75 will be bridged by the contact segment 43 of the controller14 and circuits established for actuating coil of switches '76, 77, and-78,- respectively. The

switches '76 to '78, inclusive, are disposed to shunt sections 79, 80and til/respectively, of the resistor 47. When all of theseresistorsections have been shunted full field excitation will be provided forthe motor 1 so that full tractive effort may be developed during thestarting of the train. The energizing circuit for the actuating coil ofthe switch "76 .may be traced from the junction point 39 throughconductor 40, contact fingers "41 and '73, bridged by contact segment43, con- 'ductor' 82, the actuatingcoil of switch '76- and conductor 83,theactuating coil of the switch 7-? and conductors 67 and 27 back to thebattery 21. i i

Similarly, the energizing'circuit of the switch. 78 may be traced fromthe junction point 39 through conductor 40, contact fingers 41 and 75,conductor 84, the actuating coil of switch '78 and conductors 6'7 and 27to the battery 21.

Since the actuating coils of the switches '76, 77 and '78 are energizedsimultaneously, the switches will all be closed to shunt the entireresistor4'7. Full voltageis therefore applied to the field winding 10 sothat the motor may start with full field excitation;

In order to maintain fullfield excitation on the motor until fullvoltage has been impressed on its armature by thegenerator 2,thecontroller is so arranged that the switches 76, '77 and 78 willremain closed until full voltage has been applied to the motor.

In order to increase the speed of the motor 1, while the motor isoperating with full field excitation, the-voltage applied thereto may beincreased in steps. This may be accomplished by shunting sections of theresistor 49 step-by-step so as to increase the voltage developed by thegenerator 2. Sections of the resistor 49 maybe shunted step-by-step byactuating the controller 14: through positions 0, d and c.

When the controller has been actuated to position 0, a circuit isestablished for an actuating coil of a switch 86. This circuit may betraced from the junction point 39 through conductor 40, contact fingers41 and (Tl-bridged by contact segment 43-conductor 88, the actuatingcoil of the switch 86 and conductor 27 to the battery 21. Therefore, theswitch 86 is closed to shunt section 89 of the resistor 49. Therefore,the current through the field winding 13 of the generator 2 is soincreased that the voltage developed by the generator is increased. Thevoltage of the generator 2 having been increased, the speed of the motorwill increase also.

When the controller 14 has been actuated by position (I, an energizingcircuit for an actuating coil or a switch 91 is established. Thiscircuit may be traced from the junction point 39 through conductor 40,contact fingers 41 and 92-bridged by contact segment 43-conductor 93,the actuating coil of switch 91 and conductor 27 to the battery 21.Therefore, switch 91 is closed and a section 94 of the resistor 49 isshunted whereby the current through the field winding 13 is furtherincreased, which increase in field current will cause the voltagedeveloped by the generator 2 to increase also. This voltage increasewillcause the motor to increase its speed.

When the controller has been, actuated to the position 6 or its fullvoltage position, an energizing circuit for an actuating coil of aswitch 95 is established. This circuit may be traced from the junctionpoint 39 through conductor 40, contact fingers 41 and 96, conductor 97,the coil of switch 95 and conductor 27 to the battery 21. Therefore, theswitch 95 is closed and a section98 of the resistor 49 is shunted,whereby the field current through the field winding 13 is still furtherincreased. The voltage of' the generatorZ and the speed of the motor 1will, therefore, beincreased also.

'Whenth'e controller 1i has been actuated to its full voltage position,that is, the position in which the generatoris supplying full voltage tothe motor while it is operating with full field excitation,

the speed of the motor 1 maybe increased bydecreasing the currentthrough thefield winding 10 stp-by-step. In order to decrease the fieldexcitation of the motor 1, step-by-step, the controller 3.4 may beactuated through positions f, g and h.

By'actuating the controller 14 through positions 1, g and h,respectively, the energizing circuits, above traced, for the actuatingcoils of the switches '76, '77 and '78 will be deenergized successively.Therefore, the sections 79, and'8-1' of resistor 47 will be reconnectedsuccessively, or step-by-step into the circuit of the field winding 10.The field excitation of the motor '1 will,

therefore, be decreased in steps until the motor has reached its fullrunning speed.

If it may be assumed that the controller 14 is V in its full runningposition, and that the motor 1 is operating at its full running speed,and that itis desired to cause the motor 1 to regenerate current anddrive the generator 2 as a motor which inturn will drive thesynchronousmotor 4 as a'n'alternating current generator, the controller14 may be actuated towards its ofi position. In so doing the fieldexcitation of the motor 1 will be increased and the field excitation ofthe generator 2, with continued movement of controller towards the oifposition, is decreased. Since the motor 1 under these conditions isdriven by the momentum of the vehicle, the voltage developed bythe-motor lwill exceed that developed by the generator 2, henceregenerative braking will be effected. However, it isto be noted thatwhen the controller is in its ofi position, the switches3'l and 38 willbe opened to disconnect the motor lfrom the generator 2.

to efiect emergency braking; 'In such cases, it is desirable that thepower applied to the motor be interrupted as quickly as possible andpref? erably at the instant when the current flowing from thegeneratorto the motor passes through zero value.

In order'to causetheswitch 38 to open the erator to the motor passesthrough zero or approximately zero value, a push button switch 99 isprovided for deenergizing the actuating coil of the switch 38. Theswitch 99 is so arranged thatn when actuated-to its open circuitposition,

the 'engineers handle ofthe controller' 74, as

shown in Fig. 1,1or in 1 any otherconvenient location. I f

If the motor 1 is motoring and an emergency moment that'the currentflowing from'the genarises which requires that'the'power. be interrupted as quickly as possible from the motor,

the push-buttonswitch 99 may be depressed and they controller 14.-actuated towards the off position.

fore, the moment the counter 'electrom'ot'ive'ifo'rce In doing so themotorjl will act as agenerator in theiman'nerhereinbefor' set forth.There,-

or the voltage developed by the motor 1, is approximately equal, to thevoltage developed by the generator 2, the current flowing from themotorto, the generator will be zero: or substantially zero and therelay'59 will open its contact members 66 whereby the circuit for theactuating coil for the switch 38 is deenergized, to cause the switch 38to open.

When the power supply for the motor is interrupted,, emergency braking,as by air brakes or other suitable braking means, may be employed tobring the vehicle to a stop. It is to be noted that until the contactmembers 66 of the relay 59 have opened, the circuit for the actuatingcoil of the switch 38 will not be interrupted eventhough the contactmembers of the switch 99 are open, because the energizing circuit of theactuating coil of theswitch 38 will be maintained through the contactmembers of the relay 59 in the manner hereinbefore set forth.v I

I If it be assumed that the vehicle is moving at a speed at which themotor 1 is regenerating current, that is, operating as a generator andan emergency should arise requiring thatv the power supply to the motorbe interrupted as quickly as possible, then, inorder to cause the switch38 to open when the current flowing from the motor to the generatorpasses through zero, the push button switch is depressed and the airbrakes applied. Inthis case the controller need not be moved towards its01f position, because when the brakes are applied the vehicle will slowdown to a speed at which the motor will cease to regenerate and start toact as a motor to accelerate the vehicle. The moment the motor changesfrom generating tomotoring, the relay 59 will open. Therefore, theswitch 38 will open in the same manner as hereinbefore described. 7

The control system employed for governing the operation of the vehiclepropelled by the mo tor 1 is also adapted to that class of service whichrequires intermittent application of power to the motor 1 while thevehicle is coasting or drifting without causing shocks to the trainpropelled by the vehicle. Ordinarily, intermittent application of powerwill result in violent shocks to the train because of abnormal currentsurges from the generator to the motor, or-vice versa,

this position the sWitchesBS and 37 will be open.

- If it be further assumed that the vehicle is coasting and that it isdesired to reconnect the motor 1 to the generator 2, then the moment theswitch 37 is closed, the motor l and the generator 2 will be suppliedwith equalor approximately equal amounts of field excitation. Since themotor 1 is being driven by, the momentum of the vehicle, it may bepossible that the armature of the motor is notrotating at-the samespeedas the armature of the generatorftherefore, it will be apparentthat the voltage developed by the 7 motor may not beequal to that of thegenerator 2.

If the voltages are not equal or approximately so, .the difierentialrelay 54 will operate to prevent the establishment of the energizingcircuit for the actuating coil of the switch 38 until these voltages areequal, or approximately equal.

fIherefore, the engineer or operator will be re- .Iherefore, shocks tothe motor and the vehicle quired to actuate the controller 14 to thatposition in which equal voltages will be developed bythe generator 2 andthe motor 1, before a closing of the switch 38 can be effected. Whenthiscondition obtains, the differential relay 54 will close its contactmembers and permitthe energizing circuit for the coil of theswitch 38 tobe established. Therefore, the switch 38 will .close only Whenthevoltages developed by the generator 2 and themotor 1 are substantiallyequal. Since the switch 38'closes under such conditions there will be noappreciable current surges from the motor to the generator or from thegenerator to the motor as the case may be.

will be diminished to a point at which they are not objectionable, ifany shocks should result.

Since various modifications maybe made in the invention herein describedwithout departing from thespirit and. the scope thereof, it is desiredthat the embodiment ofthe invention herein disclosed shall beinterpreted in an illustrative and not a limiting sense. e

We claim as our invention: 7 e

1. In a control system, in combination, a traction motor for propellinga vehicle, a generator for supplying power to said motor, a singlecontroller for successively varying the voltage of the generator and themotor to approximately equal values while the vehicle'is in motion,means for automatically connecting the motor to the generator when. saidvoltages are approximately equal, means for automatically disconnectingthe motor from the generator when the current flowing through them is ata low value, and manually operable means for controlling, the operationof said disconnecting means.

2. In a control system for motor vehicles provided with a generator, aprime mover therefor, anda traction motor, in combination, means for 115 connecting the motor to the generator, a controller for successivelyincreasing the generator excitation and decreasing the motor excitationto effect acceleration of the vehicle, means for automaticallydisconnecting said motor from the generator when the current traversingthe motor and generatorv passes through a relatively low predeterminedvalue, as the controller is moved towards the off position, and manuallyoperable means for controlling the operation of said disconnectingmeans.

3. In a control system for motor vehicles provided with a generator, aprime mover therefor,

and a traction motor, in combination, means for connecting the motor tothe generator, a controller for successively increasing the generatorexcitation and decreasing the motor excitation to eiiect acceleration.of the vehicle,.means for connecting and disconnecting the motor fromthe generator at will. while the vehicle is in motion, said means beingdisposed to preclude reconnecting of themotor to the generator until themotor counter voltage is approximately equal to the generator voltage,and means for preventing the motor from being disconnected from thegen-I.

erator when the motor current exceeds a predetermined value.

4. In a control system for a motor vehicle pro vided with a generator, aprime mover for the generaton and a traction motor, said generator andtraction motor being provided with armature and field windings, incombination, a switch for connecting said motor to the generator, a coilfor actuating said switch, means for establishing a switch closingcircuit for said coil, and means responsive to the current flowing in acircuit including said motor and generator for establishing a holdingcircuit for said switch actuating coil.

5. In a control system for a motor vehicle provided with a generator, aprime mover for the generator, and a traction motor, said generator andtraction motor being provided with armature and field windings, incombination, a switch for connecting said motor to the generator, a coilfor actuating said switch, means for establishing a switch closingcircuit for said coil, and electromagnetic .means responsive to thecurrent flowing in a circuit including said motor and generator forestablishing a holding circuit for said switch operating coil.

deenergization of said. actuating coil when saidcurrent has reached apredetermined value provided the switch has been actuated.

DANA R. STAPLES. ELDEN I. STAPLES.

